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BUG: KCSAN: data-race in ktime_get_real_seconds / timekeeping_advance

write to 0xffffffff8603db08 of 280 bytes by interrupt on cpu 0:
 timekeeping_advance+0x893/0xd80 include/linux/string.h:359
 update_wall_time+0x19/0x20 kernel/time/timekeeping.c:2137
 tick_do_update_jiffies64+0x1ae/0x260 kernel/time/tick-sched.c:94
 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138
 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1289
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x288/0x600 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
 __kcsan_setup_watchpoint+0x282/0x510 kernel/kcsan/core.c:469
 __tsan_read8 kernel/kcsan/kcsan.c:31 [inline]
 __tsan_read8+0x2c/0x30 kernel/kcsan/kcsan.c:31
 ifname_compare_aligned include/linux/netfilter/x_tables.h:413 [inline]
 ip6_packet_match net/ipv6/netfilter/ip6_tables.c:72 [inline]
 ip6t_do_table+0x4bd/0xf20 net/ipv6/netfilter/ip6_tables.c:307
 ip6t_mangle_out net/ipv6/netfilter/ip6table_mangle.c:52 [inline]
 ip6table_mangle_hook+0x167/0x310 net/ipv6/netfilter/ip6table_mangle.c:74
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x83/0x160 net/netfilter/core.c:512

read to 0xffffffff8603db78 of 8 bytes by task 7523 on cpu 1:
 ktime_get_real_seconds+0x20/0x40 kernel/time/timekeeping.c:127
 xfrm_lookup_with_ifid+0x688/0x1300 net/xfrm/xfrm_policy.c:3127
 xfrm_lookup net/xfrm/xfrm_policy.c:3174 [inline]
 xfrm_lookup_route+0x44/0x100 net/xfrm/xfrm_policy.c:3185
 ip6_dst_lookup_flow+0xde/0x120 net/ipv6/ip6_output.c:1156
 rawv6_sendmsg+0x7ac/0x2140 net/ipv6/raw.c:926
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7523 Comm: syz-executor.3 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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